Amp Meet Two - The Results

These are the results of the power and performance test conducted on the 7th April 2010 at the second Amplifier Meet in Peckham, London.

All power measurements are Maximum continuous output power in RMS watts* per channel, two channels driven to the threshold of clipping at 40 Hz, 1 kHz, and 10 kHz, and at loads of 8 ohm, 4 ohm and 2 ohm unless otherwise stated in the notes. Bridge power ratings are CALCULATED based on the amplifier's performance into 4R and 2R loads. 8R Bridge = 2 × 4R per channel; 4R Bridge = 2 × 2R Per channel. Inclusion of a calculated bridge rating does not necessarily mean the amp is bridgeable - PKN and Powersoft for example. "Continuous" means 5 seconds or greater - this ensured that the amplifiers were not damaged by the testing, and meant a sensible number of amplifiers could be tested in the alotted time. "Burst" (<100ms) ratings were not measured.

THD+N = Total Harmonic Distortion plus Noise and is a measure of the purity of the amplifier output as well as its noise level. It was measured at the maximum power output at various frequencies and load impedances. Anything below 1% is fine, below 0.1% is better. Obscure results sometimes appear because of distortion cancellation mechanisms.

Some amplifiers were not measured at 2R because they may have been damaged by the test. Exclusion of a 2R measurement does not mean the amplifier will not withstand 2R LOUDSPEAKER loading. Sine testing into a dummy load is considerably more demanding of an amplifier.

All amplifiers were fed from the same supply, adapted according to the mains plug fitted. 32A, 16A and 13A was available.

The mains voltage was not measured on the day. This fact has caused considerable debate on internet forums and may account for the fact that some manufacturers' amplifiers performed below their stated specification. Despite the central London location of the test, the mains voltage may have been lower than normal which can affect the maximum power obtainable from an amplifier, especially toroidal and non-PFC SMPS amplifiers. We implemented mains-voltage measurements at amp meet three. We would welcome the opportunity to repeat these tests in a more tightly controlled environment in our lab. Please get in touch with us if you would like to send us an amplifier to test.